(concurring).
Although I concur with the decision of the majority to reverse the forfeiture order and remand for further proceedings, I write separately to express the view that the evidence of the dog sniff should not be admitted at any new trial. I conclude that the evidence of the dog sniff is inadmissible both because it is not relevant under Minn. R. Evid. 401 and because it does not qualify as expert testimony under Minn. R. Evid. 702 and 703.
I have no doubt that certified drug detection dogs provide valuable assistance to law enforcement in the investigation of a crime. Likewise, I agree that such a dog’s alert may provide probable cause to support a search. But in a trial, proof that contraband is present or has contaminated other property should not be shown by the fact of the dog’s alert, but by scientific tests performed on the contraband or contraband contaminated property that is discovered during the search. It is unlikely that anyone would argue otherwise in a criminal context, and I find no basis for making any evidentiary distinction simply because forfeitures are civil proceedings that are subject to different burdens of proof.
Before applying the evidentiary rules, I will first state a series of interrelated concerns I have with the use of a dog’s alert as substantive evidence to prove the chemical composition of the object of that alert.
There are at least two serious layers of subjectivity involved in dog sniff evidence. There is first the subjectivity of the interpretation by the dog’s handler of the actions of the dog. Unlike the gauge on a breathalyzer, the movements of a dog are imprecise and they are not subject to precise verification. Of course, the dog handler is the witness at trial and can be cross-examined about his or her interpretation, but the subjectivity that depends on the handler’s familiarity with the dog, the handler’s care to avoid a “handler’s clue,” and the handler’s ability to extrapolate from a controlled testing environment to the endlessly variable environments present in the field, cannot be eliminated and cannot be tested by cross-examination.1
*532In the record before us, for example, Officer Frisby discussed the dog’s alert in this imprecise way:
[H]er alert once she starts locating drug odor, is a physical change and response that she only has when she’s locating drug odor. Her alert is she closes her mouth and her breathing changes; it becomes deeper and more rapid. Once she pinpoints the source of the odor, she’ll go into an indication. * * * Her indication is an aggressive indication. She bites and scratches at the source of the odor.
Officer Frisby acknowledges that each dog may alert differently.
Of perhaps greater concern is the subjectivity of the dog. The dog is, in reality, the expert witness who is opining that the object contains an odor of contraband. On what does the dog base that opinion? Unlike a human expert witness, the dog cannot say, and unlike a mechanical measuring device, a dog is a complex organism that cannot be calibrated to eliminate errors in judgment or random false alerts. Of course, the dog cannot explain why he or she alerted to an object, and the right to cross-examine the dog’s reasons disappears into a black hole. As can be seen in the majority’s discussion of the “currency contamination theory,” it apparently is difficult for anyone to explain scientifically why a dog alerts to an object or precisely what that alert means.
These subjectivity concerns are not as material in a probable cause context, because the sniff is only used to justify the search and the ultimate proof is in the seized objects to which the dog alerted. But in the case before us, the seized objects were never tested and thus they provided no proof of contamination.
Further, a dog’s alert is nonspecific. For the dog in this case, the same alert is given for marijuana, methamphetamine, cocaine, heroin, and psilocybin mushrooms.2 Again, this failure to be specific is not a problem in the probable cause context because all five substances are illegal and the alert will provide a basis for a search for any one of those substances. But, again, the proof will be in the object that is found during the search, not in the dog’s alert. Surely, a person could not be convicted on the basis of a dog’s alert, which would indicate the presence of one or more of five illicit drugs, without evidence of which specific illicit drug was present.
A. Rule ⅛01.
I conclude that evidence of the dog sniff does not meet the requirements for relevance under Minn. R. Evid. 401, which provides that “ ‘[rjelevant evidence’ means having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.”
The forfeiture statute, as it applies to cash, authorizes forfeiture of all property “that represents proceeds derived from or traceable to” the “manufacturing, compounding, processing, delivering, importing, cultivating, exporting, transporting, or exchanging of contraband or a controlled *533substance that has not been lawfully manufactured, distributed, dispensed, and acquired.” Minn.Stat. § 609.5311, subds. 2(a) and 4(b) (2006). Notably, forfeiture cannot be based on mere possession. The only evidence of an unlawful use in this record is the testimony of Carlisle that he sold marijuana out of the apartment — presumably satisfying the statutorily proscribed uses of “processing,” “exchanging,” and “delivering.” As a result, the precise question of “fact that is of consequence to the determination of [this forfeiture] action” is whether the cash in the safe represents proceeds of Carlisle’s processing, exchanging, or delivering of marijuana.
In that context, the dog’s alert to the cash only supports, at most, the inference that the cash may have been in proximity to one of five controlled substances: marijuana, methamphetamine, cocaine, heroin, or psilocybin mushrooms. Because the dog’s alert cannot be specifically interpreted as an indication of the presence of marijuana, it is not probative of the question of fact that is of consequence to the determination of the action. And, although the dog’s alert might support an inference that the cash may have been in the presence of one of the other illicit drugs, that inference is not probative of any fact that is of consequence to the determination of the action because the mere possession of any of those drugs would not satisfy the use requirements of the forfeiture statute. Because the dog sniff evidence is not probative of any “fact that is of consequence to the determination of [this forfeiture] action,” I conclude it is irrelevant under Minn. R. Evid. 401.
I reach that conclusion without needing to resolve the “debate” about the “currency contamination theory.” But were I to reach that issue, I would conclude that, by definition, the existence of the debate precludes the use of dog sniff evidence under our application of the Frye-Mack test for scientific evidence, which requires that the scientific principle be “sufficiently established to have gained general acceptance in the particular field in which it belongs.” State v. Mack, 292 N.W.2d 764, 767 (Minn.1980) (quoting from Frye v. United States, 293 F. 1013, 1014 (D.C.Cir.1923)). On the scientific questions of whether most of the currency in circulation is contaminated with trace amounts of cocaine, and whether dogs alert to the residue of cocaine on currency or only to the byproduct, methyl benzoate, I have these observations:
1. There is no evidence in this record on the issue, nor have we decided any other case where the competing scientific studies were adequately developed in the record or where we determined which point of view — contamination or no contamination, cocaine or methyl benzoate — ■ has gained general acceptance in the scientific community. In such a situation, the majority is on thin ice when it attempts to resolve these debated scientific issues by relying on the interpretation given by other courts to selected scientific studies that were not even tested in the evidentiary record before those courts and were considered in the context of different legal standards — for example probable cause versus clear and convincing evidence, and Frye-Mack versus Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993). Surely, the rejection of the contamination theory is not so firmly established in the scientific literature as to be subject to judicial notice.
2. As noted, many of the established cases that reject the contamination theory have done so without a developed record and, as revealed by their opinions, without a comprehensive review of the scientific studies. Foremost among these is the decision in United States v. Funds in Amount of $30,670.00, relied upon by the *534majority. 403 F.3d 448, 457-59 (7th Cir.2005). The court begins its analysis by acknowledging that there “appears to be some scientific and legal debate” regarding the “probity of dog alerts to currency.” Id. at 453-54. The court then notes that there is a further scientific debate on “whether dogs alert only to cocaine itself or rather to the odor of a cocaine byproduct, such as methyl benzoate.” Id. at 455. To resolve these scientific debates, the court invited the parties to submit scientific articles at the appellate level — none existed in the evidentiary record and no hearing had been conducted to elicit or test competing scientific opinions.
The court ultimately criticized the scientific articles and case law relied on by the claimant because, although studies show that “70-90% of circulated paper currency in major U.S. cities is contaminated with trace amounts of cocaine,” some other studies conclude “that dogs likely do not alert to cocaine itself but rather to methyl benzoate,” which evaporates rapidly from currency. Id. at 456-57 (emphasis added). The court then relied on the studies presented by the government that had been performed by Drs. Kenneth Furton and Stefan Rose and that criticized the currency contamination theory. The court essentially adopted the conclusions of Drs. Fur-ton and Rose that “dogs do not alert to byproducts other than methyl benzoate and would not alert to synthetic ‘pure’ cocaine unless methyl benzoate was added.” Id. at 457-58. In other words, the court did not address the issue relevant to a Frye-Mack test, namely, whether the theories of Drs. Furton and Rose were generally accepted in the scientific community. Instead, the court, acting as fact finder at the appellate level, simply decided that the theories of Dr. Furton and Rose were scientifically correct.
3. In sharp contrast to the seventh circuit’s approach, the other recent cases, relied on by the seventh circuit as having stepped back from the currency contamination theory, apparently had an evidentia-ry record of opinion testimony on these debated scientific issues. See, e.g., United States v. $22,474.00 in U.S. Currency, 246 F.3d 1212, 1216 (9th Cir.2001) (noting that the “government presented evidence that the dog would not alert to cocaine residue” but would only “alert to the odor of a chemical by-product of cocaine called methyl benzoate,” and that the government’s evidence that the dog would not have alerted unless the currency had recently been in the proximity of cocaine was undisputed); United States v. $242,484.00, 389 F.3d 1149, 1165-66 (11th Cir.2004) (noting that “no one with any expertise testified in support of [the claimant’s] ever-lasting scent, global contamination theory” and, to the contrary, the claimant had elicited evidence that there is a shelf life to narcotics on currency). In fact, the ninth circuit, after $242,484.00, made it clear that a dog sniff alert does not provide “sufficient evidence of a meaningful connection between seized money and illicit drugs unless the dog is trained to perform, and performs, a sophisticated dog alert” — meaning, that the state “must present evidence that the drug detection dog ‘would not alert to cocaine residue found on currency in general circulation [and that] the dog was trained to and would only, alert to the odor of a chemical by-product of cocaine called methyl benzoate.’ ” In re $80,045.00 in U.S. Currency, 161 Fed.Appx. 670, 671-72 (9th Cir.2006) (quoting $22,474.00 in U.S. Currency, 246 F.3d at 1216.).
4. The cases that appear to adopt the methyl benzoate theory of dog sniff drug detection do not discuss the fact that methyl benzoate is a common chemical used in multiple consumer products — solvents, insecticides, perfumes, etc. Perhaps the *535underlying studies eliminate the possibility that a dog may alert to the innocent presence of methyl benzoate from the use of those products, but the court decisions that discuss the studies do not so indicate. The majority opinion here must rely solely on the broad, untested conclusions of other courts because we have no scientific evidence in the record before us.
5. The record before us has none of the specificity that is required to constitute foundation for a “sophisticated dog sniff,” even in those courts that have rejected the currency contamination theory. Officer Frisby, the dog’s handler, was clearly not qualified to testify about the scientific debate that surrounds cocaine. And, contrary to the conclusion reached by the majority that dogs do not alert to cocaine residue, Officer Frisby testified that this dog had been trained to alert to “the base odors and derivatives” of five illicit drugs, including cocaine. Officer Frisby could not establish any basis for a “sophisticated dog sniff,” as defined by the ninth circuit, because he was not qualified to testify that the dog would not alert to cocaine but would only alert to methyl benzoate. And, as everyone apparently agrees, Officer Frisby was not qualified to testify to the evaporation rates of methyl benzoate on currency.
6. Our inability to resolve the scientific debate concerning cocaine is not made irrelevant because this case involves marijuana. In fact, our concerns should be even greater because we have not been provided with any studies that identify what chemical element in marijuana causes a dog to alert and none of the decisions of other courts refer us to such studies. We have no information about whether dogs alert to the residue of marijuana or to some derivative and, if the latter, whether that derivative commonly exists in innocent consumer products.
One could argue that this case should not be analyzed under the scientific evidence rules because a dog’s alert is not scientific. This, of course, begs the question. If the dog’s alert is not scientific proof of the existence of a chemical on currency, what is it? If it is less than scientific — that is, if it is not an objective phenomenon that can be explained and verified, why should a court permit the fact finder to give it any weight? And, surely, it is not more than scientific.
Based on the record before us, and the state of scientific literature on the subject, I conclude that a dog sniff is irrelevant to prove the chemical composition of an object and the admission of dog sniff evidence as substantive evidence of the contamination of currency by an illicit drug violates Rule 401 and our Fryer-Mack test. This conclusion would not unduly hamper law enforcement because the dog sniff may still be used as an investigative tool and, when it results in the discovery of contraband or contraband contaminated property, law enforcement can rely on the scientific testing of that contraband and property.
B. Rules 702 and 703.
I also conclude that evidence of the dog sniff does not meet the requirements of Minn. R. Evid. 702, which provides that a qualified expert witness may testify to opinions on matters that involve “scientific, technical, or other specialized knowledge” if it “will assist the trier of fact to understand the evidence or to determine a fact in issue,” or Minn. R. Evid. 703, which requires that the facts or opinions of an expert witness be of the “type reasonably relied upon by experts in the particular field.” Both rules deal with the foundation that must be laid before expert opinion evidence is admissible.
*536The majority acknowledges that the foundation for the use of the dog sniff was lacking because Officer Frisby could not provide a clear answer on the dog’s error rate; did not introduce documentation supporting the dog’s training; and provided no evidence on the dog’s reliability under the field conditions. The majority suggests that the county should be given an opportunity to supply further foundation on remand at a new trial. I disagree for several reasons.
First, for the reasons stated above, I conclude that the dog sniff is not relevant and thus is not admissible no matter what further foundation is added.
Second, I see no reason to provide the county a second opportunity to develop further foundation. The county had the opportunity to present evidence of the dog’s error rate, training process, and the effects of the field conditions at the first trial. The majority’s conclusion that the county failed to provide sufficient foundation would lead me to conclude that the dog sniff evidence cannot be used in any new trial because the county has not identified any compelling reason to excuse the county’s failure to provide sufficient foundation at the first trial.
. Our longstanding rule against the admissibility of lie detector tests is based in part on the inability to remove subjectivity from the operator's interpretation. See, e.g., State v. Kolander, 236 Minn. 209, 221-22, 52 N.W.2d 458, 465 (1952).
We have no doubt that the lie detector is valuable in investigative work of law enforcement agencies and may frequently lead to confessions or the discovery of facts which may ultimately lead to the solution of many crimes; but we are in accord with the rule that the lie detector has not yet attained such scientific and psychological accuracy, nor its operators such sureness of interpretation of results shown therefrom, as to justify submission thereof to a jury as *532evidence of the guilt or innocence of a person accused of a crime.
Id. (emphasis added). Of course, a lie detector test deals with a defendant’s credibility, not a physical fact, so our lie detector rule is not directly applicable.
. Conceivably, the same alert might be given for elements of any of these five combination drugs, even when those elements might exist in another, completely legal form, i.e., Su-dafed as an element of methamphetamine or methyl benzoate as an element of common solvents, insecticides, or perfumes.